Fine bubble supply device

Abstract

To provide a fine bubble supply device of a simple aspirator system and with a simple structure which is capable of stably and efficiently generating a constant amount of fine bubbles per unit time by using artificial gas from an artificial gas supply source such as a small gas cylinder of a small capacity and a mini gas cartridge and of supplying a small amount of measurement object part with the fine bubbles.SOLUTION: A fine bubble supply device 1 supplies, with a liquid feed pump 20, a part 11 to be measured with liquid containing fine bubbles 12 generated by sucking artificial gas from an artificial gas supply source 50 into an aspirator 30 that sucks and conducts liquid from the liquid part 11 to be measured or its peripheral environment with the liquid feed pump 20. The device has a capacity-variable buffer vessel 40 which equalizes pressure of the artificial gas to peripheral pressure of the part 11 to be measured in the middle of a flow path between the artificial gas supply source 50 and the aspirator 30.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fine bubble supply device used in laboratories or measurement sites to stably convert artificial gas from a small gas cylinder into fine bubbles, introduce them into a measurement target such as a relatively small amount of liquid to be measured, expel and replace the dissolved gas, and obtain accurate measurement data. [Background technology]

[0002] When fish are raised in closed fish pens or tanks, the dissolved oxygen concentration in the water decreases due to the fish's breathing. To maintain an appropriate dissolved oxygen concentration, oxygen gas or air is blown into the water to increase the dissolved oxygen concentration.

[0003] Furthermore, in the field of water treatment, such as boiler water and circulating cooling water, dissolved oxygen can cause corrosion of pipes. To remove the dissolved oxygen, nitrogen gas is blown into the water to replace the dissolved oxygen with nitrogen.

[0004] Fine bubbles (microbubbles with diameters on the order of 1 to 10 μm, e.g., several tens of μm, or nanobubbles with diameters of several tens to 1,000 nm) are used to efficiently introduce and replace these gases. Known methods for generating fine bubbles include high-speed shearing, pressurized collapse, cavitation, and aspirator. For example, Patent Document 1 discloses a deoxygenation device for removing dissolved oxygen from specific water, such as underwater or seawater, by circulating nitrogen gas in a nanobubble state through the water and replacing the dissolved oxygen with nitrogen, thereby reducing or removing the dissolved oxygen in the water. The device includes a nitrogen gas injection unit that injects nitrogen gas into the water to be treated, and a stack of multiple plates, each plate having a flat surface through which the nitrogen-injected water passes, with multiple holes arranged in the plate's upper and lower grooves in the direction of the hole arrangement, and the upper and lower grooves intersecting at the holes.

[0005] Among the methods for generating fine bubbles, the aspirator method is particularly widely used. Patent Document 2 discloses a microbubble generator for use with the aspirator method, which includes a casing with one end opening and the other end opening at both ends in the longitudinal direction, a gas-liquid mixing means for introducing gas into the casing, a straightening cylinder installed inside the casing 4, a first propeller-type blade row fixed to the outside of the straightening cylinder, and a second propeller-type blade row fixed to the inside of the straightening cylinder.

[0006] This type of aspirator method generates fine bubbles by sucking in air or artificial gases from gas cylinders, etc., that form fine bubbles into the water flow that passes through the aspirator, and can be used in a wide range of applications, from large to small, such as fish pens, pools, aquariums, and laboratory containers.Since the structure of the aspirator is relatively simple, there is no need for a complex and expensive fine bubble generator, and fine bubbles can be introduced cheaply and easily.

[0007] When it is desired to sufficiently dissolve fine bubbles of introduced gas in a specified amount of water using the aspirator method, measures are taken to increase the amount of fine bubbles generated and introduced per specified time. Patent Document 2 states that there is a limit to the amount of fine bubbles (microbubbles) generated per specified time, and that in practice, the upper limit of the liquid flow rate is said to be approximately 15 to 30 liters per minute, and that the volume of gas in the liquid is said to be in the range of approximately 1 to 10 percent in terms of void fraction.

[0008] In the aspirator method, when the gas to be aspirated is air drawn from the ambient atmosphere surrounding the device, a gas flow regulator and, if necessary, a gas flow meter and pressure gauge are used to adjust the amount of gas supplied to the aspirator. A gas flow regulator using a needle valve is used as this type of gas flow regulator. The needle valve adjusts the flow rate by the degree of opening of the conical needle-type release valve, and adjustment is made using a gas flow meter and pressure gauge.

[0009] Fine bubbles are generated by drawing a constant amount of large volumes of introduced gas into the aspirator per unit of time, such as atmospheric air or artificial gases such as oxygen, nitrogen, or argon gas from outdoor nitrogen gas tanks or large gas cylinders (a 47-liter gas cylinder containing approximately 7,000 liters of gas at atmospheric pressure, a 40-liter gas cylinder containing approximately 6,000 liters, or a 10-liter gas cylinder containing approximately 1,500 liters). Even when a sufficient amount (e.g., 0.5 to 5 liters per minute) of introduced gas such as atmospheric air or artificial gas from an outdoor nitrogen gas tank or large gas cylinder is drawn into the aspirator, there is little or no change in the supply gas pressure or flow rate per unit of time. Therefore, once the gas flow rate is adjusted with the needle valve, there is no need to readjust it.

[0010] However, when an artificial gas such as oxygen gas, nitrogen gas, or argon gas is introduced into an aspirator at a rate of, for example, 0.5 to 5 L per minute from a small gas cylinder with a relatively small capacity (a 3.4 L gas cylinder that holds approximately 500 L at normal pressure) or a handy mini gas cartridge, or so-called spray can (a 10 mL mini gas cartridge that holds approximately 4.4 L, a 15 mL mini gas cartridge that holds approximately 6.6 L, a 60 mL mini gas cartridge that holds approximately 20 to 26 L, or a 95 to 98 mL mini gas cartridge that holds approximately 18 to 40 L depending on the type of gas), the internal pressure of the cartridge gradually decreases, causing the flow rate per unit time to fluctuate and temporarily decrease, or, because the internal pressure is not very high, the flow rate per unit time may fluctuate sequentially in accordance with changes in the external temperature or the operating pressure of the ejection valve. In such a case, it is extremely difficult to uniformly adjust the gas flow rate by simply adjusting the degree of opening of the jet valve or adjusting the flow rate with a needle valve midway through the flow path in the early stages.

[0011] If it were to adjust the degree of release of the ejection valve of a small gas cylinder or mini gas cartridge in real time according to the flow rate measurement results from the small gas cylinder or mini gas cartridge, or to adjust the flow rate with a needle valve midway through the flow path, a large-scale adjustment mechanism would be required, which would be impractical for a simple and small aspirator-type fine bubble generator. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-116555 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-21343 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been made to solve the above-mentioned problems, and aims to provide a simple and easy-to-use aspirator-type fine bubble supply device that can stably and efficiently generate a constant amount of fine bubbles per unit time using artificial gas from an artificial gas supply source such as a small-capacity gas cylinder or mini gas cartridge, and that can supply a small amount of fine bubbles to a measurement target. [Means for solving the problem]

[0014] The fine bubble supply device made to achieve the above object is: A sample solution is placed in an open measurement container. Liquid measurement target Department or The liquid is then pumped With suction tube Aspirate The liquid is sent to the measurement target part through an outflow tube. Conducting aspirator Through , Consists of a gas cylinder, gas cartridge, or spray can containing an artificial gas From anthropogenic gas sources The aforementioned A fine bubble supplying device that supplies fine bubble-containing liquid generated by sucking artificial gas to the measurement object part using the liquid supply pump, A pressure measuring device for measuring the pressure of the artificial gas at the ambient pressure of the measurement object is provided in the middle of the flow path between the artificial gas supply source and the aspirator. Atmospheric pressure is and pressure equalization The syringe is made of either a bag made of flexible resin film that expands or contracts so that the pressure becomes equal to the atmospheric pressure, or a piston syringe in which a movable piston is slidably inserted into a cylinder, thereby making the volume variable so that the pressure becomes equal to the atmospheric pressure. It is characterized by having a variable volume buffer container.

[0015] This fine bubble supply device includes the variable volume buffer container. Internal pressure but so that the pressure is equal to the atmospheric pressure , and maintaining the volume of the artificial gas in the variable-volume buffer container within a certain range. The flow rate of the artificial gas is Flow control valve Adjust according to the degree of release regulator of In the flow path, between the variable volume buffer vessel and the artificial gas supply source It is preferable that it has

[0016] This fine bubble supply device is While the pressure is equalized with the atmospheric pressure, When the volume of the artificial gas falls below a lower threshold, the artificial gas is fed to the variable-volume buffer container or the amount of the artificial gas is increased, and when the volume exceeds an upper threshold, the feeding of the artificial gas is stopped or the amount of the artificial gas is reduced. The aforementioned Adjuster In the flow path, between the variable volume buffer vessel and the artificial gas supply source It may be that the device has the following characteristics.

[0017] This fine bubble supply device is While the pressure in the variable-volume buffer container is equalized with the atmospheric pressure, a mass flow controller that adjusts the volume of the artificial gas in the variable volume buffer container to be constant; In the flow path, between the variable volume buffer container and the aspirator It may be that the device has the following characteristics.

[0018] This fine bubble supply device is Oso When the volume of the tank exceeds a predetermined amount, an overflow mechanism is installed to release the tank to the outside until the volume reaches a predetermined amount. , the variable volume buffer container It may be that the device has the following characteristics.

[0019] This fine bubble supply device has the overflow mechanism 、 or A branched portion in the flow path between the variable volume buffer vessel and the artificial gas supply source Excess gas exhaust line 、 It is preferable to have a check valve to prevent backflow of outside air. [Effects of the Invention]

[0020] The fine bubble supply device of the present invention traps the artificial air pressure in a variable-capacity buffer container and equalizes it with the ambient pressure, even if the supply flow rate of the artificial gas from an artificial gas supply source such as a small-capacity gas cylinder or mini gas cartridge fluctuates over time or temporarily. As a result, a constant amount of artificial gas is supplied to the aspirator per unit time, allowing the aspirator to stably and efficiently generate a constant amount of fine bubbles per unit time.

[0021] This fine bubble supply device does not necessarily require the use of a gas flow meter or pressure meter, and does not require the adjustment of the degree of opening of the artificial gas supply source's jet valve in real time or the adjustment of the flow rate with a needle valve midway through the flow path.It can be configured simply and can easily and reliably control the gas flow rate, thereby stably and efficiently generating a constant amount of fine bubbles per unit time.

[0022] This fine bubble supply device is equipped with a variable-capacity buffer container that can buffer even slight fluctuations in the gas flow rate, eliminating the need to constantly adjust the gas flow rate from the artificial gas supply source using complicated methods such as gas flow rate measurement and feedback.It can reliably replace dissolved gases, such as dissolved oxygen, in the measurement target area with fine bubbles from the artificial gas, even when the measurement target area is small, such as in laboratory-scale measurements or on-site measurements in the ocean, rivers, and lakes.

[0023] This fine bubble supply device is highly versatile because it can be constructed using a general-purpose aspirator or liquid delivery pump that is commercially available or can be manufactured as needed, and also using a simple structure such as an easily available variable-volume buffer container such as a bag, cylinder, or piston.

[0024] This fine bubble supply device can stably and efficiently generate a constant amount of fine bubbles per unit time, whether at normal pressure, under high-pressure conditions such as in the ocean or on the seabed, or under low-pressure conditions such as at high altitudes, and can therefore be used to reliably and accurately measure the measurement target regardless of location or environment. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic diagram showing a fine bubble supply device to which the present invention is applied. [Figure 2] FIG. 1 is a plan view showing an aspirator of a fine bubble supply device to which the present invention is applied. [Figure 3] FIG. 1 is a schematic diagram showing another embodiment of a fine bubble supplying device to which the present invention is applied. [Figure 4] FIG. 1 is a schematic perspective view showing a variable-volume buffer container of a fine bubble supply device to which the present invention is applied. [Figure 5] FIG. 10 is a plan view showing another embodiment of a variable-volume buffer container of the fine bubble supply device to which the present invention is applied. [Figure 6] FIG. 10 is a plan view showing another embodiment of a variable-volume buffer container of the fine bubble supply device to which the present invention is applied. [Figure 7] FIG. 10 is a schematic diagram showing a part of a fine bubble supplying device according to another embodiment of the present invention. [Figure 8] FIG. 10 is a schematic diagram showing the state of use of a fine bubble supplying device according to another embodiment of the present invention. [Figure 9] FIG. 10 is a schematic diagram showing the state of use of a fine bubble supplying device according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments for carrying out the present invention will be described in detail, but the scope of the present invention is not limited to these embodiments.

[0027] The fine bubble supply device 1 of the present invention will be explained with reference to Figure 1, which shows a schematic diagram thereof. It is a device that introduces fine bubbles 12 of artificial gas into a liquid measurement object portion 11, such as a sample solution, to replace dissolved gas, such as dissolved oxygen, in the measurement object portion 11 with the artificial gas.

[0028] The fine bubble supply device 1 is connected to a liquid measurement object 11, and includes a liquid pump 20, an aspirator 30, a variable-volume buffer container 40, and an artificial gas supply source 50.

[0029] This fine bubble supply device 1 is specialized for introducing fine bubbles 12 of artificial gas into a liquid measurement object 11 of a small amount, for example, a maximum of 1 L, preferably 1 mL to 500 mL, more preferably 3 to 250 mL, specifically 5 to 200 mL, using an artificial gas supply source 50 such as a small gas cylinder containing a maximum of about 500 L of artificial gas, preferably about 20 to 40 L at room temperature, or a mini gas cartridge containing at most about 5 L.

[0030] In addition, it is preferable that the fine bubble supply device 1 always connects the variable-volume buffer container 40 and the artificial gas supply source 50, but it may also be configured to separate or block the artificial gas supply source 50 from the variable-volume buffer container 40 after a sufficient amount of artificial gas has been introduced from the artificial gas supply source 50 into the variable-volume buffer container 40.

[0031] Artificial gases include nitrogen gas, argon gas, helium gas, oxygen gas, carbon dioxide gas, ammonia gas, and mixtures of any two or more of these gases.

[0032] A sample solution, which is a liquid measurement object 11, is contained in an open measurement object container 10, such as a beaker. A liquid supply pump 20 is connected to the sample solution 11 via an intake tube 21 that draws in the sample solution 11. A liquid supply pump 20 extends from the intake tube 21 to an aspirator 30, delivering the liquid solution to the aspirator 30. The outlet tube 22 is connected to the aspirator 30 via an aspirator inlet connector 31. The sample solution flow path 32 narrows within the aspirator 30 at the aspirator inlet connector 31 and continues to the aspirator outlet connector 33. Inside the aspirator 30, the sample solution flow path 32 merges with an artificial gas intake flow path 35. An outlet tube 36, whose diameter expands at the aspirator outlet connector 33 connected to the sample solution flow path 32, extends from the aspirator 30, with its open end 36a immersed in the sample solution 11 in the measurement object container 10.

[0033] Meanwhile, an artificial gas supply source 50, such as a small gas cylinder or mini gas cartridge, is connected via piping tube 54 to a regulator 53 having a flowmeter or pressure gauge 52 and a main valve 51 for adjusting the open / close state. If necessary, a flow control valve 55, such as a needle valve, is provided along the piping tube 54. The piping tube 54 branches off at a T-shaped pipe 56 and is connected to a branch tube 41. The branch tube 41 is inserted into an airtight variable-volume buffer container 40, such as a sealed bag, via a variable-volume buffer container inlet connector 42. The variable-volume buffer container inlet connector 42 and the variable-volume buffer container 40 are heat-sealed, so that the tip hole 41a of the branch tube 41 communicates with the interior of the variable-volume buffer container 40 while preventing leakage to the outside. If necessary, a check valve 57 is provided along the piping tube 54. The tip of the piping tube 54 is connected to the aspirator 30 , where the piping tube 54 is connected to the artificial gas suction flow path 35 via the aspirator inlet connector 34 .

[0034] The aspirator 30 is also known as an aspirator or ejector type, and generates fine bubbles by using the principle of drawing an external fluid into a high-pressure fluid through a constriction or nozzle. As shown in the cross-sectional view of the sample solution flow path 32 and the artificial gas intake flow path 35 in Figure 2, this aspirator 30 has the artificial gas intake flow path 35 joining the straight sample solution flow path 32 from a diagonal rearward side toward the downstream end of the flow path, so that the artificial gas can be easily drawn into the sample solution flow path 32 from the artificial gas intake flow path 35. While Figure 2 shows an example in which the artificial gas intake flow path 35 joins the sample solution flow path 32 from a diagonal side, a T-shaped vertical joining path (not shown) is also possible. The inner diameters of the sample solution flow path 32 and the artificial gas intake flow path 35 are not particularly limited as long as the aspirator 30 uses a water jet to draw in the artificial gas and generate fine bubbles. However, because this fine bubble supply device 1 uses an artificial gas supply source 50 such as a small gas cylinder or mini gas cartridge to introduce fine bubbles into a small amount of liquid measurement target 11, it is preferable that the inner diameters of sample solution flow path 32 and artificial gas intake flow path 35 are not too large. Specifically, the inner diameters of intake tube 21, and the inner diameter W1 of delivery tube 22, inner diameter W3 of outlet tube 36, and inner diameter W4 of piping tube 54 are each 0.5 to 10 mm, preferably 1 to 5 mm, more preferably 1 to 3 mm, specifically 2 mm, and the inner diameter W2 of sample solution flow path 32 and inner diameter W5 of artificial gas intake flow path 35 are each 0.05 to 1 mm, preferably 0.1 to 0.5 mm, more preferably 1 to 0.25 mm, specifically 0.2 mm.

[0035] Such an aspirator 30 is made of a transparent hard resin, such as polycarbonate (PC) or acrylic (PMMA), or an opaque hard resin, such as polyether ether ketone (PEEK), and can be fabricated by bonding a hard resin plate into which the sample solution flow path 32 and the artificial gas intake flow path 35 are engraved to a flat hard resin plate, by three-dimensional printing molding, or by cutting holes for the sample solution flow path 32 and the artificial gas intake flow path 35 with a drill.

[0036] The fine bubbles 12 of the artificial gas formed by such an aspirator 30 are minute bubbles with a diameter of about 100 nm to 10 μm, approximately 1 μm.

[0037] The variable-volume buffer container 40 is not particularly limited as long as it is airtight and can constantly trap the artificial gas, but a preferred example is an airtight bag made of flexible resin film. The variable-volume buffer container 40 traps the artificial gas and equalizes it with atmospheric pressure, while buffering fluctuations and changes over time in the flow rate and pressure of the artificial gas from the artificial gas supply source 50, so that a constant amount of artificial gas can be constantly delivered per unit time to the aspirator 30. This makes it possible to deliver a constant amount of fine bubbles made of artificial gas per unit time to the aspirator 30, even when using an artificial gas supply source 50 such as a small gas cylinder or mini gas cartridge, whose flow rate and pressure fluctuate and change over time over a short period of time with use.

[0038] The variable-volume buffer container 40 includes a flow control valve 55 that adjusts the flow rate of the artificial gas depending on the degree of release, thereby enabling the volume of the artificial gas within the variable-volume buffer container 40 to be maintained within a constant range. The flow control valve 55 may be adjusted manually or automatically so that the bag that is the variable-volume buffer container 40 is inflated with the artificial gas during measurement of the liquid measurement object 11. For example, in this case, a needle valve, a solenoid valve, or a ball valve is used as the flow control valve 55. While the flow control valve 55 is illustrated in FIG. 1, a flow meter (mass flow meter: MFM) may be used instead of or in addition to the flow control valve 55. The flow control valve 55 may be adjusted by a drive circuit according to the reading of the mass flow meter 58, or an MFC (mass flow controller) may be used.

[0039] Another example of adjusting the variable volume of the variable volume buffer vessel 40 is to measure the volume of the artificial gas flowing into the aspirator 30 with a mass flow meter (MFM) 58 (see FIG. 1), which is provided as needed, and then control the degree of opening of the flow rate adjustment valve 55 with a drive circuit according to the reading of the mass flow meter 58 so that only the volume of the artificial gas recognized by the digital conversion circuit flows into the bag or piston syringe that constitutes the variable volume buffer vessel 40, thereby adjusting the volume of the variable volume buffer vessel 40 to a constant level. The flow rate adjustment valve 55, which adjusts the flow rate with the drive circuit according to the reading of the mass flow meter 58, may be located between the mass flow meter 58 and the variable volume buffer vessel 40, and an auxiliary pump may also be located on the variable volume buffer vessel 40 side.

[0040] The system may also include a regulator that supplies artificial gas to the variable-volume buffer container 40 when the volume of the artificial gas in the variable-volume buffer container 40 falls below a lower threshold and stops supplying artificial gas when the volume exceeds an upper threshold. When the variable-volume buffer container 40 is a bag, the regulator, as shown in FIG. 3 , has pressure sensors installed inside and outside the bag. When the outside of the bag (variable-volume buffer container 40) touches the pressure sensors, it detects an upper limit, and when the inside of the bag touches the pressure sensors, it detects a lower limit. This allows the regulator to sense upper and lower volume thresholds. When a comparison circuit detects that the upper threshold is exceeded, a drive circuit closes or tightens the flow control valve 55. Conversely, when the comparison circuit detects that the lower threshold is exceeded, the drive circuit opens or loosens the flow control valve 55. Preferably, the regulator monitors the volume of the variable-volume buffer container 40 and controls the on / off of the flow control valve 55 so that the volume is between the upper and lower thresholds. For example, as shown in Figures 11(a) to 11(c), the pressure sensor may be configured with an electrode pair consisting of electrode 46b arranged on the upper exterior of the bag of the variable-volume buffer container 40 and electrode 46a arranged above the bag, which detects the upper threshold when the electrodes 46a and 46b come into contact with each other when the volume of the artificial gas exceeds the upper threshold and the bag becomes over-inflated, and an electrode pair consisting of electrode 46c arranged inside the upper surface of the bag and electrode 46d arranged inside the lower surface of the bag, which detects the lower threshold when the electrodes 46c and 46d come into contact with each other when the volume of the artificial gas falls below the lower threshold and the bag becomes over-deflated. Alternatively, although not shown, the pressure sensor may be a capacitance-type pressure sensor that detects pressure by a change in capacitance caused by an applied force (for example, the force pushing up on the sensor when it is over-inflated and the gravity of the weight when it is over-deflated) instead of an electrode pair, or a pressure-sensitive conductive rubber-type pressure sensor that detects pressure by a decrease in the resistance value of an insulating rubber mixed with a conductive material in response to an applied force.The pressure sensor may be a 1-axis, 3-axis or 6-axis force sensor that detects forces in the length, width, and height directions, as well as moment planes and actions; a capacitance-type force sensor that detects the shape distortion of the bag caused by the applied force or moment by changes in the capacitance of a capacitor; or a strain gauge-type force sensor that detects the shape distortion of the bag caused by the applied force or moment using a strain gauge sensor.

[0041] Alternatively, as shown in FIG. 4, an image of the variable-volume buffer container 40 is taken with a camera 47, and the image is compared with control images taken in advance of the container in a range from a deflated state to an excessively inflated state. Through image recognition, when it is recognized that the bag that is the variable-volume buffer container 40 is excessively inflated as shown in FIG. 4(a), the drive circuit closes or tightens the flow control valve 55, and when it is recognized that the bag is deflated as shown in FIG. 4(c), the drive circuit opens or loosens the flow control valve 55, thereby keeping the volume of the artificial gas inside the variable-volume buffer container 40 within a certain range.

[0042] While a bag has been used as an example of the variable-volume buffer container 40, it may also be an airtight piston syringe made of resin, metal, or glass, connected to a branch tube 41, in which a plunger 44 with a rubber gasket 44a attached to its tip is slidably inserted within an outer cylinder 43, as shown in FIG. 5(a). Alternatively, it may be an airtight piston syringe made of resin or metal, connected to a branch tube 41, in which a movable piston 44' is slidably inserted within a cylinder 43', as shown in FIG. 5(b). One example of adjusting the volume of the piston syringe serving as the variable-volume buffer container 40 is to have a position sensor that detects the position of the plunger 44 or piston 44'. When a position sensor detects that the upper threshold position is exceeded, a drive circuit closes or tightens the flow control valve 55, and when a position sensor detects that the lower threshold position is exceeded, the drive circuit opens or loosens the flow control valve 55. Instead of a position sensor, the upper and lower threshold positions may be determined using image recognition.

[0043] The maximum variable capacity of the variable-volume buffer container 40 is, for example, 10 mL to 10 L, preferably 50 mL to 1 L, and specifically 100 to 200 mL.

[0044] 1 to 5, as shown in FIG. 6, the piping tube 54, the variable-volume buffer container 40, and / or the branch tube 41 may be provided with an overflow mechanism that releases the artificial gas to the outside when the volume of the artificial gas in the variable-volume buffer container 40 exceeds a predetermined amount, until the artificial gas reaches a predetermined amount. For example, as shown in FIG. 6(a), the variable-volume buffer container 40 may be a piston syringe, and at the portion where the plunger 44 or piston exceeds a predetermined upper limit position, a check valve may be directly provided on the outer tube 43 or cylinder as an overflow mechanism 45 that releases excess artificial gas but prevents backflow of outside air, or an open hole and a check valve connected to it. Also, as shown in FIG. 6(b), the variable-volume buffer container 40 may be a bag, and as an overflow mechanism 45 (45') that opens when excessive pressure is reached, a check valve may be directly provided, or an open hole and a check valve connected to it may be attached to the outer wall of the bag's artificial gas storage section.

[0045] As shown in FIG. 7, the excess gas exhaust line may have a check valve 56 to prevent backflow of outside air.

[0046] The artificial gas supply source 50 contains 500 L or less at atmospheric pressure equivalent, and is a small gas cylinder (3.4 L capacity containing approximately 500 L at atmospheric pressure equivalent) or a handy mini gas cartridge, so-called spray can (10 mL capacity containing approximately 4.4 L, 15 mL capacity containing approximately 6.6 L, 60 mL capacity containing approximately 20 to 26 L, or 95 to 98 mL capacity containing approximately 18 to 40 L).

[0047] Since this fine bubble supplying device 1 supplies fine bubbles to a small amount of the measurement target portion 11, the flow rate of the artificial gas supplied from the artificial gas supply source 50 is adjusted to about 1 to 1000 mL / min, preferably 5 to 200 mL / min, and more preferably 10 to 50 mL / min. The flow rate of the artificial gas is adjusted to about 2 to 1 / 100, preferably 1 / 2 to 1 / 10, of the flow rate per unit time of the sample solution circulated by the liquid supply pump 20.

[0048] The liquid delivery pump 20 is not particularly limited as long as it can suck in a sample solution through the intake tube 21 and deliver the sample solution through the delivery tube 22. Examples of suitable pumps include a peristaltic pump, an impeller pump, a diaphragm pump, a bellows pump, and a syringe pump, which deliver liquid by squeezing the intake tube 21, which is a soft tube made of silicone or the like, with a roller. The liquid delivery pump 20 may be either a pulsating or non-pulsating type, with the non-pulsating type being preferred. The liquid delivery pump is designed to deliver a small amount of liquid to the measurement target 11, and is therefore capable of delivering a flow rate of 1 to 500 mL / min, preferably 20 to 200 mL / min, and more specifically, approximately 100 mL / min.

[0049] The fine bubble supply device 1 is used as follows, with reference to the drawings. First, a sample solution, which is the liquid measurement object 11, is placed in a measurement object container 10. Next, the pump 20 is driven to draw in the sample solution through the intake tube 21 and deliver it through the delivery tube 22. The sample solution then passes through the aspirator 30 and is returned to the measurement object container 10 through the delivery tube 36. On the other hand, when the main valve 51 of the artificial gas supply source 50 is opened and a predetermined amount of artificial gas is flowed into the piping tube 54 while being adjusted with a flowmeter or pressure gauge 52, the artificial gas accumulates in the variable-volume buffer container 40, reaches the aspirator 30, and is drawn into the sample solution flow path 32 through the artificial gas intake path 35, forming fine bubbles of the artificial gas. Fine bubbles 12 are then discharged from the open end 36a of the outlet tube 36 into the measurement object container 10 together with the sample solution. The artificial gas gradually dissolves in the sample solution due to the fine bubbles 12 of the artificial gas, and is eventually replaced by the artificial gas. At this time, the artificial gas is adjusted to a nearly constant level in the variable-volume buffer container 40 by any of the methods shown in Figures 3 to 7.

[0050] The fine bubble supply device 1 is useful for introducing a small amount of artificial gas fine bubbles from a small artificial gas supply source into a measurement target area and replacing dissolved gas with artificial gas while buffering the gas in the variable-volume buffer container 40. However, it is not suitable for introducing a large amount of fine gas bubbles from a large artificial gas supply source (the atmosphere, or a gas tank or large gas cylinder) into a swimming pool or fish pen. This is because when a large artificial gas supply source is used, pressure fluctuations and flow fluctuations are unlikely to occur in a short period of time, making the use of the variable-volume buffer container 40 unnecessary and, in fact, making it more complicated and not providing the desired effect.

[0051] Figure 1 and other figures show an example of introducing fine bubbles of artificial gas, such as nitrogen gas, into a liquid sample solution (specifically, a sample aqueous solution or sample suspension) in an open-system measurement container 10, such as a beaker, in an indoor laboratory or measurement room to expel and replace dissolved oxygen. However, the measurement target can also be the seabed, ocean, underwater, lake, or river. In this case, a liquid can be drawn from a surrounding environment deemed to have the same water quality as the measurement target using a liquid delivery pump, and fine bubbles can be introduced into the measurement target. For example, as shown in Figure 8(a), an underwater condition measurement device 60 equipped with a fine bubble supply device 1 is deployed from a ship. When measuring various data at a desired depth, the fine bubble supply device 1 is activated to supply fine bubbles to the seawater being measured by various sensors. This allows for measurements of various parameters of seawater at specified depths in the ocean, specifically, accurate measurements of parameters such as carbon dioxide partial pressure by replacing the air with fine bubbles of nitrogen gas. Furthermore, as shown in Figure 1(b), a spear-shaped external cylinder 70 containing a built-in monitoring sensor and a seafloor subsurface condition monitoring device 71 containing a built-in fine bubble supply device 1 are used. The spear-shaped external cylinder 70 is pierced into the seafloor soil to measure the circulation status and physicochemical properties of seafloor groundwater in the soil below the seafloor, and the methane gas concentration of seafloor methane hydrate. The fine bubble supply device 1 is driven to supply fine bubbles to the seawater being measured by various sensors, and the fine bubbles are replaced with nitrogen gas to accurately measure items such as methane gas concentration. This system can be applied to aqueous solutions and suspended water, as well as supercritical water. Note that Figures 1(a) and 1(b) do not show the artificial gas supply source, variable-volume buffer vessel, intake tube, delivery tube, and piping tube, as they are hidden. [Example]

[0052] Below, a fine bubble supplying device of an embodiment to which the present invention is applied and a fine bubble supplying device of a comparative example to which the present invention is not applied will be described.

[0053] Example 1 The fine bubble supply device 1 shown in Figure 1 used a 500 mL mini-gas cartridge containing approximately 4.5 L of nitrogen gas (equivalent to atmospheric pressure) as the artificial gas source 50, a Tedlar bag (manufactured by AS ONE Corporation; Tedlar is a registered trademark) made of polyvinyl fluoride resin as the variable-volume buffer container 40, a peristaltic pump as the pump, a needle valve as the flow control valve 55, and a needle valve and flow meter (mass flow meter) as the flow control valve 58. 100 mL of tap water was used as the sample solution to be measured 11. The needle valve and flow meter of the flow control valve 58 were operated in conjunction to remove dissolved oxygen while adjusting the flow rate to 20 mL / min, as shown in Figure 1. A dissolved oxygen sensor (Mettler-Toledo: Product name: Seven2Go DO meter S9) was inserted into the sample solution to measure the dissolved oxygen concentration. The fine bubble supply device 1 was operated, and the fine bubble-containing sample solution was circulated through the sample solution. The correlation between the elapsed time and the dissolved oxygen concentration is shown in Figure 9(a). The right side of Figure 9(a) shows an enlarged scale of the dissolved oxygen concentration shown on the left side of the figure.

[0054] As is clear from Figure 9(a), the dissolved oxygen concentration of the sample solution was initially approximately 7 mg / L, but this decreased to approximately 1 mg / L two minutes after the fine bubble supply device 1 started operating, to approximately 0.1 mg / L after four minutes, and to 0.01 mg / L after six minutes.

[0055] (Comparative Example 1) The dissolved oxygen concentration of 100 mL of tap water sample solution was measured in the same manner as in Example 1, except that the variable-volume buffer container 40 was not used. The results are shown in Figure 9(b). The right graph in Figure 9(b) is an enlarged view of the dissolved oxygen concentration of the left graph.

[0056] As is clear from Figure 9(b), the dissolved oxygen concentration of the sample solution was initially about 7 mg / L, but two minutes after the start of operation of the fine bubble supply device 1, it decreased to about 1 mg / L, as in Figure 9(a). After four minutes, it was about 0.25 mg / L, and after six minutes, it was about 0.12 mg / L. The rate of decrease was slower than in Figure 9(a). This is thought to be because the variable-volume buffer container 40 was not used, and the gas supply pressure decreased during operation of the device, resulting in a decrease in the gas supply amount.

[0057] Therefore, as is clear from FIGS. 9(a) and (b), the use of the variable-volume buffer container 40 was effective. [Industrial Applicability]

[0058] The fine bubble supply device of the present invention is useful for introducing a small amount of artificial gas fine bubbles from a small artificial gas supply source into the measurement target area, replacing the dissolved gas with the artificial gas, eliminating the effects of the dissolved gas, and performing various physical and chemical analyses of the measurement target area. [Explanation of symbols]

[0059] 1 is a fine bubble supply device, 10 is a container for the measurement object, 11 is a measurement object part (sample solution), 12 is fine bubbles, 20 is a liquid transfer pump, 21 is an intake tube, 22 is a delivery tube, 30 is an aspirator, 31 is an aspirator inlet connector, 32 is a sample solution flow path, 33 is an aspirator outlet connector, 34 is an aspirator inlet connector, 35 is an artificial gas intake flow path, 36 is an outlet tube, 36a is an open end, 40 is a variable capacity buffer container, 41 is a branch tube, 42 is a variable capacity buffer container inlet connector ctor, 43 is the outer tube, 43' is a cylinder, 44 is a plunger, 44' is a piston, 45 and 45' are overflow mechanisms, 46a to 46d are electrodes, 47 is a camera, 50 is an artificial gas supply source, 51 is a main valve, 52 is a flow meter or pressure gauge, 53 is a regulator, 54 is a piping tube, 55 is a flow control valve, 56 is a T-pipe, 57 is a check valve, 58 is a mass flow meter, 60 is an underwater condition measuring device, 70 is a spear-shaped outer tube and monitoring sensor, 71 is a seabed underground condition monitoring device, and W1 to W5 are inner diameters.

Claims

1. A fine bubble supply device in which a liquid containing fine bubbles is generated by sucking in an artificial gas from an artificial gas supply source consisting of a gas cylinder, gas cartridge, or spray can containing an artificial gas, via an aspirator that is connected so that the liquid is sucked in from a liquid measurement object portion that is made of a sample solution and placed in an open measurement object container using a liquid feed pump through an intake tube and sent to the measurement object portion through an outlet tube, and then the liquid is supplied to the measurement object portion using the liquid feed pump, A fine bubble supply device characterized by having, in the middle of the flow path between the artificial gas supply source and the aspirator, a variable-capacity buffer container consisting of either a bag made of flexible resin film that expands or contracts so that the pressure of the artificial gas is equal to atmospheric pressure, which is the ambient pressure of the measurement object, or a piston syringe with a movable piston slidably inserted into a cylinder, thereby changing the volume so that the pressure is equal to atmospheric pressure.

2. 2. The fine bubble supply device according to claim 1, further comprising a regulator in the flow path between the variable volume buffer container and the artificial gas supply source, which regulates the flow rate of the artificial gas by adjusting the degree of opening of a flow control valve so that the pressure in the variable volume buffer container is equal to the atmospheric pressure and the volume of the artificial gas in the variable volume buffer container is maintained within a certain range.

3. The fine bubble supply device according to claim 2, characterized in that the regulator is provided in the flow path between the variable volume buffer container and the artificial gas supply source, and the regulator supplies or increases the amount of the artificial gas to the variable volume buffer container when the volume of the artificial gas falls below a lower threshold, while maintaining the pressure inside the variable volume buffer container equal to the atmospheric pressure, and stops or reduces the supply of the artificial gas when the volume exceeds an upper threshold.

4. A fine bubble supply device as described in claim 1, characterized in that it has a mass flow controller in the flow path between the variable capacity buffer container and the aspirator, which adjusts the pressure in the variable capacity buffer container to be equal to the atmospheric pressure while maintaining a constant volume of the artificial gas in the variable capacity buffer container.

5. The fine bubble supply device according to claim 1, characterized in that the variable-volume buffer container has an overflow mechanism that releases the artificial gas in the variable-volume buffer container to the outside when its volume exceeds a predetermined amount until it reaches a predetermined volume.

6. The fine bubble supply device according to claim 5, characterized in that the overflow mechanism or the excess gas exhaust line branching off from between the variable volume buffer container and the artificial gas supply source in the flow path has a check valve to prevent backflow of outside air.

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